CODEWITHSUNDEEP
rlistregressionformula
R starter
R starter

Reputation: 197

Is there any simple way to create a list of formula in R

Here I want to create a list of formula for a simple linear regression, 2nd and 3rd order polynomial models. I just did this. It could be ok for a few variables but my data is a quite lot variables. So how could I avoid overloading work using another way to do the same thing?

ind1.lm <- lm(dep ~ ind1, data = df)
ind1.qd <- lm(dep ~ poly(ind1, 2, raw = TRUE), data = df)
ind1.cb <- lm(dep ~ poly(ind1, 3, raw = TRUE), data = df)

ind2.lm <- lm(dep ~ ind2, data = datAll)
ind2.qd <- lm(dep ~ poly(ind2, 2, raw = TRUE), data = df)
ind2.cb <- lm(dep ~ poly(ind2, 3, raw = TRUE), data = df)

ind3.lm <- lm(dep ~ ind3, data = df)
ind3.qd <- lm(dep ~ poly(ind3, 2, raw = TRUE), data = df)
ind3.cb <- lm(dep ~ poly(ind3, 3, raw = TRUE), data = df)

formula.list <- list(as.formula(ind1.lm), as.formula(ind1.qd), 
    as.formula(ind1.cb), as.formula(ind2.lm), as.formula(ind2.qd), 
    as.formula(ind2.cb), as.formula(ind3.lm), as.formula(ind3.qd), 
    as.formula(ind3.cb))

 formula.list

Thanks in advance!

Upvotes: 2

Views: 1939

Answers (1)

G. Grothendieck
G. Grothendieck

Reputation: 269654

Define the independent variables and the formats of the formulas and from that we can get the formula strings. Since lm accepts strings as formulas we can then apply over that giving a list of lm objects whose names are the formulas.

ind <- c("ind1", "ind2", "ind3")
fmt <- c("dep ~ %s", 
         "dep ~ poly(%s, 2, raw=TRUE)", 
         "dep ~ poly(%s, 3, raw=TRUE)")

fo.strings <- c(outer(fmt, ind, sprintf))

sapply(fo.strings, lm, data = df, simplify = FALSE)

Questions to SO should include reproducible code and df was omitted from the question but we can run it using the builtin anscombe data frame like this:

fmt <- c("y1~ %s", 
         "y1~ poly(%s, 2, raw=TRUE)", 
         "y1 ~ poly(%s, 2, raw=TRUE)")
ind <- c("x1", "x2", "x3")
fo.strings <- c(outer(fmt, ind, sprintf))
sapply(fo.strings, lm, data = anscombe, simplify = FALSE)

Upvotes: 5

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